ej,
Vivian Creek is open. I was there last Saturday. I went up with Microspikes, but would advise you wear crampons. The Microspikes were worthless. I'm not quite sure, but I believe the trail disappears at around 9,000 ft. There is at least two very big slopes you will have to slog up, and it's steep. I suppose you can do it with just your boots, but it is very laborious. Trust me, with the Microspikes, I took five steps, slid a few feet...rinse and repeat.
It can also be very dangerous. Depending on how you decide to summit, whether make a direct line up or traverse over, a fall/slide can be disastrous without an ice axe. I don't know what it's like this week. I don't mean to be dramatic, it was a tough hike, but not a killer. I still had a big smile at the end of the day. I saw a few guys around the 8,000 foot level coming up in tennis shoes and laughed.
Also, you might want to bring Deet or some bug spray. A lot of water and mud at the start, and the bugs were out in force when we were coming back.
